I am looking to get two additional gauges to monitor the temps on my 337 ci flathead engine. One will be a more accurate Oil Pressure Gauge than stock. The second will be a temperature gauge. Should I go with an Oil Temp gauge or a Coolant Temp Gauge? Why would coolant temps be more imprtant than oil temp or visa-versa. I start with about 32 psi oil pressure cold. After about 15-20 minutes driving, my oil pressure slowly drops to critical levels. I'm thinking the oil is getting too hot and thinning the oil. The radiator has not been boiling over.
The new gauges will be mounted on a panel below the dash - exact location not yet determined.
If you are not running 20W50 oil, then you should start using it in your engine. Also a quart of Lucas Oil Stabilizer wouldn't hurt. As for the temperature gauge, I would go for a good water temperature gauge. Excessive enine heat will show up in the coolant first. The oil takes longer to heat up, so the water temperature gauge will give you an earlier warning of an engine overheat condition.